During drilling operations, drilling fluids, which may also be referred to as drilling muds, are circulated through the wellbore to cool the drill bit and maintain the wellbore. Also during drilling operations, a cement slurry may be introduced into the wellbore to secure the structure of the wellbore. Drilling muds may be either aqueous or hydrocarbon-based and vary in composition.
Under some conditions, the presence of drilling muds in the wellbore negatively affects the performance of the cement slurry. In these conditions, it is sometimes desirable to pass a spacer fluid through the wellbore.